The present invention relates generally to a decalcomania, and more particularly to a sublimation decalcomania of the surface of a wrist watch case.
There are a variety of methods for printing words or designs on the surface of an object. One of the methods is known as the sublimation decalcomania comprising a specially prepared paper on which a decal is printed for transferring to the surface of an object made of glass, wood, metal, etc. The ink of the decal is transferred to the surface of the object by the heat sublimation of the ink when the object and the decal-bearing paper are baked together.
The conventional method comprises a first step involving the coating of an adhesive on the surface of an object to be processed. The decal-bearing paper is attached manually to the coated surface of the object. In light of the manual operation of the conventional method described above, the conventional method is time-consuming and inefficient at best. In addition, the quality of work done by the conventional method is often poor in view of the fact that the decal-bearing paper is not evenly and intimately joined with the surface of the object. Such a problem becomes more acute when the surface of the object is irregular and wrinkled.
As illustrated in FIG. 1, a wrist watch has a metal case A formed of a main body A1 and two watchbands A2 extending in opposite directions from the main body A1. The conventional sublimation decalcomania described above is not suitable for use in printing the surfaces of the main body A1 and the watchbands A2. In light of such a technical infeasibility, the surfaces of the main body A1 and the two watchbands A2 are electroplated. The coating of a decorative design or picture on the metal case A of the wrist watch by the electroplating process is monotonous and far from being exquisite.
A cheap wrist watch often has a plastic case which is coated with decorative designs or pictures by a web fed press. In spite of the designs or pictures being versatile, the feel of the plastic watch case is much lower in quality than that of the metal watch case.
The primary objective of the present invention is to provide a cost effective and high-quality sublimation process of transferring a decorative picture or design from a decal-bearing paper to the surface of a watch case.
The sublimation decalcomania of the present invention comprises a first step in which the surface of a watch case is provided with a foundation coat. A decal-bearing paper is then prepared such that the size of the decal-bearing paper is corresponding in size to the area of the foundation coat of the watch case surface. An airtight soft bag of a plastic material is also prepared such that the airtight soft bag is provided with an opening. Upon completion of the drying of the foundation coat, the watch case and the decal-bearing paper are put into the soft bag such that the printed surface of the paper is in contact with the foundation coat of the watch case surface. The soft bag containing the paper and the watch case is kept in an airtight space, which is subsequently exhausted of air along with the bag until the inner walls of the bag are intimately joined together, thereby forcing the printed surface of the paper to be in an intimated contact with the foundation coat. The bag is then sealed off before the bag is baked in an oven to bring about the transfer of a decorative design or picture to the surface of the foundation coat of the watch case from the decal-bearing paper. The transfer is attained by sublimation. Finally, the watch case is removed from the bag such that the remainder of the decal-bearing paper is separated from the watch case.